docs: def kplfrm(frmcls, outCell=None):
      """
      Return a SPICE set containing the frame IDs of all reference
      frames of a given class having specifications in the kernel pool.
  
      http://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/cspice/kplfrm_c.html
  
      :param frmcls: Frame class.
      :type frmcls: int
      :param outCell: Optional output Spice Int Cell
      :type outCell: spiceypy.utils.support_types.SpiceCell
      :return: Set of ID codes of frames of the specified class.
      :rtype: spiceypy.utils.support_types.SpiceCell
      """
      if not outCell:
          outCell = stypes.SPICEINT_CELL(1000)
      frmcls = ctypes.c_int(frmcls)
      libspice.kplfrm_c(frmcls, ctypes.byref(outCell))
      return outCell